1. Field of the Invention
The present invention relates generally to MOS circuitry, and more particularly to MOSFET circuitry which detects or responds to a pulse-edge.
2. Description of Prior Art
MOS (metal oxide semiconductor) technology is in a state of development, and is contributing substantially to growth of the electronics industry in general and particularly to the computer or data processing industry. The earlier bipolar technology is still extensively employed however, and both semiconductor techniques can be expected to be viable in the future.
For example, MOS field effect transistors (FETs) are employed in computer memories today, where data is stored in the memories in the form of voltages. That is, a binary "1" (or lack thereof, a "0") can be temporarily retained as a voltage on capacitors or capacitance intrinsic to the MOS circuit. Since the MOS circuit is constructed on a substrate or base from semiconductor materials which physically overlap each other (to form various circuit components such as transistors, gates, and other elements), an inherent or parasitic capacitance exists between various layers of semiconductor material forming these circuit elements. It is this very capacitance which is utilized in and essential to, operation of dynamic MOS memories.
In addition to utilization of MOSFETs in computer memories, they are used in other digital circuits. One of the problems associated with digital circuits is that there can be a competing switching or timing condition, where one element or component is switching at an arbitrary time, but precisely when another element or component at a different point in the system is switching, and where these two components are so interconnected that they provide conflicting or competing results or information.
For example, in some MOS circuit designs, it is desirable to employ different logic forms, (such as two-phase ratioed, static, four-phase ratioless, etc.), to obtain the advantages of each design. But, since the different logic forms are usually not mutually compatible, various problems result including the above-noted race or timing problems of the prior art. It is thus important to be able to control the precise time of occurrence of a change of state of a particular component. The present invention solves this problem of the prior art. The present invention controls precisely the time when a circuit element will change state responsive to, and substantially simultaneously with, the occurrence of an edge of a particular control pulse. It solves this problem employing the MOS technology as will be elaborated on hereinbelow.